While some people think about how to sweat less, others think about how to use sweat for beneficial purposes.
Researchers at NTU University of Singapore have developed a new type of battery that could be ideal for future wearable devices. The battery stretches and receives the energy it needs to operate from sweat. The battery is soft and as described as flat as a bandage. The 2cm x 2cm element is attached to a flexible and sweat-wicking textile that is easy to fit into wearable devices, including smartwatches, medical devices, etc.
The developers conducted tests in which the tester put the battery on the wrist and rode a stationary bike for 30 minutes. During this time, the user generated 4.2 volts of output power and 3.9 mW, which is enough to operate a commercial temperature sensor and transfer data from the sensor to a smartphone via Bluetooth. The battery is environmentally friendly, does not contain heavy metals and harsh chemicals like other modern batteries.
The researchers say they have created a battery that will provide electronic wearable devices with a guaranteed source of energy from the human body. The team expects the battery to be able to power a wide range of devices. In addition, since a new battery does not contain harsh chemicals inside, there is no danger of acid or other corrosive substances spilling out from a ruptured battery if damaged.
NTU created a battery using printer ink containing silver flakes and hydrophilic polyurethane acrylate (HPUA). When the silver flakes come in contact with sweat, chloride ions and the acidity of the sweat cause the silver flakes to bond and increase their electrical conductivity. The chemical reaction also creates a current between the electrodes.
The stretchable textiles used absorb relatively large amounts of sweat, thus providing a constant source of energy even if the person does not sweat much. Another advantage is that, according to the authors, the battery will be more durable than existing ones.